【作者】 朱汉宝；

【导师】 周亚素；

【作者基本信息】 东华大学 ， 供热、供燃气、通风与空调工程， 2007， 硕士

【摘要】 地源热泵空调是有效利用可再生能源(地热能)的一种空调技术，具有节能、环保等特点。随着我国可持续发展方针的提出，建筑节能的呼唤声越来越响，特别是北京2008年奥运会的申办，地源热泵空调已经在我国掀起了建筑节能的新的浪潮。但目前对地源热泵空调系统的核心部件——埋地换热器的研究还不够完善，特别是土壤热物性的测试问题。这在很大程度上制约了地源热泵的应用与发展。土壤的热物性参数直接影响到埋管的深度与长度，以及埋地换热器的传热性能与经济性能。本文以垂直U型管埋地换热器为研究对象，重点做了以下几个方面的工作：(1)、建立一种适合工程应用、精度较高的垂直U型管埋地换热器传热模型。(2)、在综合分析国外土壤热响应测试仪的基础上，根据热响应原理，利用集散型计算机控制技术，研制一套以计算机数据采集和控制为核心的土壤热响应测试仪。并编写了一套方便快捷的分析实验数据、计算土壤导热系数与埋管热阻的软件。(3)、在东华大学环境学院实验室建立一套垂直U型管埋地换热器传热性能实验测试系统。(4)、利用研制的土壤热响应测试仪对实验室埋地换热器进行传热性能实验研究，并测试分析了江苏某县工程现场的三口试验井的传热性能。希望通过以上内容的研究，能对这种节能、环保的空调技术在我国的推广和普及做出一点贡献。通过一系列的理论分析和实验验证，本文得出结论主要有：本文根据传热学理论与土壤热物性特点，建立的垂直U型管埋地换热器传热模型能够方便快捷的计算出土壤的导热系数，通过实验分析该模型精确度较高。研制的土壤热响应测试仪的功能齐全、自动化程度较高。应用表明：该仪器运行平稳，数据检测精度满足科研的要求。利用ASP.NET语言编写的计算土壤导热系数软件，大大减轻了测试数据分析与结果计算的工作量。为科研与工程应用提供了极大的方便。本文采用两种方法测试土壤初始温度场：不开启水泵时，U型管壁上布置的薄膜热电阻测得的温度最低；开启水泵时，薄膜热电阻测得的温度比前者高0.15℃～0.3℃；U型管进出口平均温度比不开启水泵的直接测试法高0.5℃～3℃。埋孔深度在60m～100m之间，U型管内循环水的流速在0.8m／s～1.2m／s之间，埋管的传热率较大、热阻较小、U型管进出口温差正好处在地源热泵机组运行工况。而且并联形式埋地换热器传热性能优于串联形式。虽然双U型管形式埋地换热器增加了管材和管件的费用，但与单U型管形式的相比，能节省土地，更重要的是传热率提高了35％～45％。埋地换热器传热性能实验必须注意：本文在安装好埋管后，让试验孔静置一个星期，测试的土壤初始温度比刚安装的土壤温度降低了0-3℃～1.2℃；土壤初始温度测试必须在热响应实验前进行；热响应测试期间不能停电；在一定的输入功率下，若U型管进出口温差基本上保持不变，则传热已经达到平衡；做完一组输入功率在4～7KW之间、维期一周的热响应实验后至少让埋管静置6～8天，让温度得到恢复。更多还原

【Abstract】 Ground-source heat pump(GSHP) utilizing a long-drawn renewable energy (ground thermal energy) is a technology of air-condition. GSHP has several advantages, such as: save energy and protect environment. As continuable development policy brought forward by the government, there is more and more voice of building save energy. Especially, 2008 Olympiad holding in Beijing, GSHP has put building save energy to a new climax. However, researches on design of the ground heat exchangers are far from adequate, such as: test soil characteristic. They block the application and development of GSHP.Parameter of soil characteristic affects the depth of boreholes、the length of U-bend loops、thermal properties and economic performance of the ground loop heat exchanger. This thesis mostly researches on the ground loop heat exchanger with U-bend Pipes, and analyzes mostly as follows: (1)、Set up a heat transfer mode of the ground loop heat exchanger which is suitable for project application and has good precision. (2)、Basing on analysis of "Thermal Response Test Equipment" board or home, according to thermal response theory, design a new Thermal Response Test Equipment with a three stage distributed computer supervisory control and data acquisition(SCADA) system adopting DCS. Compile a software that can calculate conductivity of soil and the thermal resistance of boreholes. (3)、Establish a experiment testing system of the ground loop heat exchanger with U-bend Pipes in Donghua University Environment college. (4)、Experiment research of ground loop heat exchangers in our school and a town in Jiangsu province. The author wishes that the thesis could make some contribution to the air-condition technology more and more popular in China.After a series of theoretic analysis and experimental validation, the author elicited the following conclusions:According to the heat transfer theory and soil characteristic, this thesis has set up a heat transfer mode of the ground loop heat exchanger calculating conveniently and quickly conductivity of soil and the thermal resistance of boreholes. The precision of the mode is approved very high. Thermal Response Test Equipment developed by myself has complete functions and the degree of automation is very high. The data can satisfy the require of scientific research. The software compiled by ASP.NET language lightens the work of data analysis and calculation.This thesis tests the undisturbed temperature of soil by two methods: when the pump is closed, the method testing temperature logging along the borehole can react actual temperature and the result is most exact. When the pump is opened, temperature logging along the borehole is 0.15℃～0.3℃more than the former. Inlet and outlet temperature is 0.5℃～3℃more than the former. When the depth of borehole is between 60m～100m、velocity of flow in U-bend loop is between 0.8m/s～1.2m/s, there are high heat transfer rate、small resistance and suitable inlet or outlet temperature difference. Heat transfer performance of Parallel connection is better than that of in series. Although double U-bend loops need more pipes, comparing to single U-bend loop ,they can save ground and improve heat transfer rate to 35%～45 %.Thermal Response Test has some rules to comply: The ground loop heat exchanger need wait a week after grouting, soil temperature has decreased 0.3℃～1.2℃; Testing undisturbed soil temperature is ahead of the thermal response experiment. Make sure the wire is on during the thermal response experiment; It is important to know the balance of heat transfer. When the balance is to reach, we must stabilize the heat transfer rate; In order to make sure of temperature of soil coming back, the ground loop heat exchanger need wait 6～8 days after a thermal response experiment.更多还原